Scientists finds connection between early memories and autism spectrum disorder

Neuroscientists from Trinity College Dublin have uncovered a “fascinating connection” between the retention of early life memories and brain developmental trajectories associated with autism.

 

Most of us remember little of our experiences from before two years of age. This form of memory loss, termed “infantile amnesia” refers to the seemingly complete loss of episodic and autobiographical memories formed during early life. 

 

The research team at Trinity College Dublin investigated how infantile amnesia is affected by forms of autism, finding that exposure to maternal immune activation, where inflammation is artificially induced during pregnancy in the absence of infection in order to alter offspring brain development, acts as a safeguard against developmental memory loss in early life by impacting the way specialist memory cells (engrams) in the brain function.

 

The maternal immune response, sparked into life in response to infection during pregnancy, is known to contribute to the cause of autism in both humans and mice. The Trinity neuroscientists report for the first time that this altered brain state also prevents the usual loss of memories formed during infancy. 

 

Researchers also found that memories normally forgotten from infancy can be permanently reinstated if the correct memory engrams are activated in adults. These findings imply that infantile amnesia stems from a retrieval deficiency, as early childhood memories are still stored in the adult brain but cannot normally be accessed through natural recall.

 

 “Infantile amnesia is possibly the most ubiquitous yet underappreciated form of memory loss in humans and mammals,” said senior author Dr Tomás Ryan.

 

“Despite its widespread relevance, little is known about the biological conditions underpinning this amnesia and its effect on the engram cells that encode each memory. As a society, we assume infant forgetting is an unavoidable fact of life, so we pay little attention to it,” he added.

 

“These new findings suggest that immune activation during pregnancy results in an altered brain state that alters our innate, yet reversible ‘forgetting switches’ that determine whether the forgetting of infant memories will occur. This research holds significant implications for enhancing our comprehension of memory and forgetting across child development, as well as overall cognitive flexibility in the context of autism.” 

 

For further engagement and research updates see: https://www.ryanlabtcd.org/team or follow @RyanLabTCD, @TJRyan_77, @SarahDPower on X.

 

Access the study in full here.